Biological membranes are the basis for maintenance of cellular integrity and the most important factor regulating the influence of the environment on cellular function. The goal of these studies is to develop a molecular understanding of solute transport processes. The coupling of metabolic energy to solute transport will be examined through the use of genetic and biochemical techniques. We will concentrate on the role of the coupling factor (Ca, Mg ions ATPase) in this process. The mechanism of solute translocation will also be examined using the lactose phosphotransferase system of Staphylococcus aureus. Reconstitution of the isolated carrier protein, enzyme IIlac, with both lipid vesicles and "real" membranes will provide the basis for this mechanistic approach.